Fully 3D-Printed Miniature Soft Hydraulic Actuators with Shape Memory Effect for Morphing and Manipulation.

Miniature shape-morphing soft actuators driven by external stimuli and fluidic pressure hold great promise in morphing matter and small-scale soft robotics. However, it remains challenging to achieve both rich shape morphing and shape locking in a fast and controlled way due to the limitations of actuation reversibility and fabrication. Here, we report fully 3D-printed, sub-millimeter thin-plate-like miniature soft hydraulic actuators with shape memory effect for programmable fast shape morphing and shape locking. It combines commercial high-resolution multi-material 3D printing of stiff shape memory polymers (SMPs) and soft elastomers and direct printing of microfluidic channels and 2D/3D channel networks embedded in elastomers in a single print run. We demonstrated leveraging spatial patterning of hybrid compositions and expansion heterogeneity of microfluidic channel networks for versatile hydraulically actuated shape morphing, including circular, wavy, helical, saddle, and warping shapes with various curvatures. The morphed shapes can be temporarily locked and recover to their original planar forms repeatedly by activating shape memory effect of the SMPs. Utilizing the fast shape morphing and locking in the miniature actuators, we demonstrated their potential applications in non-invasive manipulation of small-scale objects and fragile living organisms, multimodal entanglement grasping, and energy-saving manipulators. This article is protected by copyright. All rights reserved.